菌斑细菌糖酵解前后胞内乳酸脱氢酶活性的研究

目的 研究细菌胞内乳酸脱氢酶(lactate dehydrogenase,LDH)在糖酵解过程中的表达特性,以了解菌斑细菌代谢的产酸机制.方法 取3种临床分离菌株(发酵乳杆菌、变形链球菌及寡发酵链球菌)和临床混合牙菌斑,在给糖前后经超声破壁后采用连续动力学法检测细菌胞内LDH活性.结果 单菌和集合菌斑细菌糖酵解前后LDH活性均无变化.但不同细菌LDH活性不同,发酵乳杆菌LDH活性[(52.91 ±8.97) U/mg]显著高于寡发酵链球菌[(0.61 ±0.05) U/mg]和变形链球菌[(0.32 ±0.07) U/mg],P＜0.01;集合菌斑LDH活性为(16.48±3.83) U/mg,加入1,6-二磷酸果糖(fructose 1,6-diphosphate,FDP)后活性显著增高[(26.37 ±8.26) U/mg] (P＜0.01).结论 不同菌种胞内LDH的活性不同,牙菌斑中存在FDP依赖型的细菌.     

牙菌斑内韦永氏菌的分离及其对致龋产酸菌的影响

本研究自人牙菌斑内成功地分离出小韦永氏球菌,将它与变形链球菌、血链球菌、唾液链球菌、干酪乳杆菌、粘性放线菌分别或混合一齐培养,结果使这些致龋菌培养液的pH值上升(唾液链球菌除外),培养液内的乳酸含量大为减少,乙酸、丙酸含量增多。     

尼古丁对口腔细菌单独或混合培养时菌群数目调控的研究

目的 探讨尼古丁对口腔细菌单独培养和混合培养中各菌群数量的调控作用.方法 将变异链球菌、格氏链球菌、缓症链球菌、口腔链球菌、唾液链球菌、血链球菌、金黄色葡萄球菌、粪肠球菌、干酪乳杆菌、表皮葡萄球菌10种口腔细菌单独或混合后置于不同质量浓度的尼古丁下培养,检测浮游状态的细菌和生物膜内的细菌各菌群数量的改变,评估尼古丁对不...     

寡发酵链球菌分子标识鉴定方法的建立

目的建立快速、有效鉴定寡发酵链球菌的方法，并验证其准确性。方法以9种口腔链球菌11株标准菌株的DNA为模板，用寡发酵链球菌16S rDNA的特异引物和乳酸氧化酶基因的引物通过PCR分别扩增这两个基因的部分片段，建立用分子标识鉴定该菌的方法。并从9个无龋的志愿者口腔中取得集合牙菌斑，在加红霉素的轻唾琼脂平板中进行培养，分离到疑似寡发酵链球菌的菌落后，用已建立的方法进行鉴定。并对初步鉴定为寡发酵链球菌的分离株进行16S rDNA序列同源性分析，以确定鉴定的准确性。结果用建立的分子标识鉴定方法，发现在11株标准菌株中只有3株寡发酵链球菌有扩增产物；用该方法鉴定为寡发酵链球菌的来自无龋志愿者牙菌斑的分离株，经16S rDNA序列同源性分析证实确实为寡发酵链球菌。结论用寡发酵链球菌16S rDNA特异性引物和乳酸氧化酶基因引物进行两步PCR来鉴定寡发酵链球菌是准确、可靠的。     

蔗糖环境对寡发酵链球菌与变异链球菌双菌种生物膜形成的影响

目的探讨蔗糖环境对寡发酵链球菌与变异链球菌双菌种生物膜形成的影响,并与血链球菌和变异链球菌的双菌种生物膜形成进行比较。方法运用菌落计数法观察蔗糖环境下唾液包被的玻璃生物模型中单/双菌株寡发酵链球菌,变异链球菌和血链球菌24 h生物膜形成情况;运用激光共聚焦显微镜观察蔗糖环境下寡发酵链球菌,变异链球菌和血链球菌单/双菌株生物模型中24h生物膜形成厚度。结果无糖环境下,单菌株模型中,菌落数:血链球菌(55.67±5.36)>变异链球菌(53.48±2.63)(P>0.05)>寡发酵链球菌(46.24±2.34)(P<0.05);生物膜厚度:血链球菌(17.23±3.82)>变异链球菌(15.16±4.21)(P>0.05)>寡发酵链球菌(10.54±4.37)(P<0.05)。双菌株模型中,变异链球菌菌落数降低幅度:血链球菌组>寡发酵链球菌组(P<0.05)。生物膜厚度:血链球菌组(8.12±2.82)<寡发酵链球菌组(11.27±3.55)(P<0.05)。蔗糖环境下,单菌株模型中,菌落数:变异链球菌(58.54±2.74)>血链球菌(51.87±5.35)>寡发酵链球菌(48.57±3.05)(P<0.05)生物膜厚度:变异链球菌(20.63±5.71)>血链球菌(13.37±4.93)>寡发酵链球菌(12.45±4.62)(P<0.05)双菌株模型中;变异链球菌菌落数降低幅度,寡发酵链球菌组>血链球菌组(P<0.05),生物膜厚度:寡发酵链球菌组(6.67±2.19)<血链球菌组(10.45±2.72)(P<0.05)。结论外界糖环境影响寡发酵链球菌和血链球菌对变异链球菌的抑制作用,蔗糖环境下,寡发酵链球菌的抑制作用强于血链球菌。     

密度感应相关性变链素及其作用分析

细菌素是由某些细菌在代谢过程中产生的一类具有抗菌活性的蛋白质或多肽,变异链球菌产生的细菌素称为变链素.变链素可能与口腔生物膜中变异链球菌的致龋性及其在牙面的定植有关.目前已有多种变链素被分离、纯化并完成了基因序列和氨基酸序列的测定,变链素与密度感应调控系统的关系及在新型抗菌制剂研发中的应用价值已受到人们关注.本文就密度...     

五种细菌致人工龋的研究

以目前认为与龋病发生关系密切的五种牙菌斑分离菌,包括变形链球菌、血液链球菌、唾液链球菌、粘性放线菌和干酪乳杆菌,采用体外实验方法,研究这些细菌致人互龋的能力。结果表明这五种细菌都可以造成釉质脱矿,产生龋样损害。这些人互龋与自然龋病理改变相似,在镜下由表及里也分为表层、表层下和损害主体三层。损害主体特点是:破坏在表层下呈水平状扩展。     

壳寡聚糖对变形链球菌黏附的影响

目的:研究壳寡聚糖对变形链球菌蔗糖依赖性黏附的影响。方法:使用不同浓度的壳寡聚糖与变形链球菌S.mutansATCC25175共同培养,计算壳寡聚糖对变形链球菌的黏附抑制率的影响,同时扫描电镜下观察变形链球菌在玻片的形态学特征。结果:变形链球菌对玻片的黏附率随培养基中壳寡聚糖浓度的升高而下降。扫描电镜图片显示壳寡聚糖组细菌间基质少,菌细胞清晰。而空白组细菌则包裹有较多的胶冻状基质。结论:壳寡聚糖可以有效抑制变形链球菌的蔗糖依赖性黏附。     

慢性根尖周炎的细菌学研究

对14例慢性根尖周炎患者16个感染根管行细菌学研究,采用2种非选择培养基和4种选择培养基在需氧和厌氧条件下孵育。结果表明厌氧菌在慢性根尖周炎感染管的混合菌感染中,有很好的检出率(87.5％和100％)。穿髓组比未穿髓组的细菌种类更多,4—9种细菌混合感口炎染型占87.5％,未穿髓组为37.5％。优势的可培养厌氧菌包括:产黑色素类杆菌、口腔类杆菌、口类杆菌、具核梭杆菌、干酪乳杆菌和内氏放线菌;比较多见的兼性厌氧菌是口腔链球菌群如血液链球菌,变链球菌。本文提出口腔正常菌群是慢性根尖周炎的潜在病原菌。     

纳米羟磷灰石/聚酰胺66作为盖髓材料的体外抗菌作用

目的研究新型纳米羟磷灰石/聚酰胺66（nHA- PA66）对龋性牙本质中常见致病菌的体外抗菌作用。方法采用变形链球菌、粘性放线菌和干酪乳杆菌的标准株,通过琼脂扩散法比较nHA- PA66固化膜片、nHA- PA66糊剂、nHA- PA66碘仿糊剂、羟磷灰石糊剂及氢氧化钙糊剂对3种实验菌的抑菌环直径大小。结果nHA- PA66固化膜片与nHA- PA66糊剂对变形链球菌无抗菌作用,对粘性放线菌和干酪乳杆菌有极轻微抗菌作用,nHA- PA66固化膜片与nHA- PA66糊剂之间抑菌环直径差异无统计学意义（P>0.05）;nHA- PA66碘仿糊剂的抗菌能力增强,但与氢氧化钙糊剂相比,二者间差异无统计学意义（P>0.05）;羟磷灰石糊剂对3种实验菌均无抗菌作用。结论nHA- PA66作为一种新型纳米生物材料,单独使用时对变形链球菌、粘性放线菌和干酪乳杆菌几乎不具有抗菌性能,但可通过与碘仿的联合应用来提高nHA- PA66用作盖髓材料时的抗菌能力。     

Evidence of the validity of a model of determinants of quality of restorative dental care

A model describing the relationship between self-reported quality of restorative dentistry and dentist characteristics for 119 Montana general dentists is presented. The best predictors formed a significant model explaining 22% of the variance of the quality measure. Results are contrasted with a previous estimation of the model for 102 Washington general practitioners. Evidence for the external validity of the model is presented.     

Experimental evidence of formation of imines in the course of reduction of hydrazones

The reduction of hydrazones is generally suggested to proceed through a reductive cleavage of the nitrogen–nitrogen bond followed by a reduction of the carbon–nitrogen bond. This sequence of reduction processes is here supported for fluorenone (V) and benzophenone (VI) hydrazones as well as by a comparison of the reduction of fluorenone and benzophenone hydrazonium ions (I,III) with corresponding imines (II,IV). Another proof of the presence of imines as intermediates is the splitting of four-electron waves of hydrazones V and VI and hydrazonium ions I and VIII into two waves at pH < 2. This has been interpreted as due to differences in slopes dE_1/2/dpH and pK_a-values of protonated hydrazine derivatives on one side and corresponding imines on the other. In this pH-range imines formed in reductions of VI and VIII are reduced in a single two-electron wave, those of I and V in two one-electron steps. Fluorenone imine (II) is sufficiently stable to allow recording of time-independent current–voltage curves between pH 6 and 11. In this pH-range the imine (II) is reduced in two one-electron steps. Benzophenone imine (IV) has been found stable between pH 4.6 and 12. At pH 4.6–8 the reduction of the imine IV takes place in a single two-electron step, at pH 8–12 in two one-electron steps. Final proof of the initial cleavage of the N–N bond is presented by comparison with the reduction of nitrones.     

不同剂型玻璃离子水门汀溶解性比较研究

目的:研究、比较不同剂型玻璃离子水门汀的溶解性和表面微观形态改变,为临床使用提供依据.方法:将3M树脂加强型玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(水粉剂型)及GC玻璃离子水门汀(双糊剂型)分别在人工唾液中浸泡30 d,冷热循环15000次,烘干测重,比较前后质量变化,计算溶解率,并用扫描电镜观察表面微观改变.结果:不同剂型的玻璃离子水门汀溶解率由高到低分别为3M树脂加强型玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(双糊剂型).3种玻璃离子水门汀经浸泡溶解后,SEM扫描表面微观形态可观察到GE玻璃离子水门汀(双糊剂型)表面形态改变较少,其他2组玻璃离子水门汀表面微观改变较多.结论:双糊剂型玻璃离子水门汀理化性能及溶解率均低于传统水粉剂型,是未来临床修复治疗的的良好选择.     

Design of clinical trials of traditional therapies of periodontitis

The present paper on the design of clinical trials of periodontal therapy first addresses the issue of the etiology of periodontal disease. It is suggested that most if not all forms of destructive periodontal disease are caused by microorganisms and that there are different forms of disease with different microbial etiologies. The progressive nature of destructive periodontal disease is subsequently discussed and it is emphasized that, in a given patient, periodontal sites which show signs of inflammation and attachment loss may not over a period of several months and years show further sign of attachment loss. The present methods of assessing periodontal disease do not allow us to discriminate between potentially active and inactive sites in untreated patients. The significance and variability of indicators of periodontal disease such as bleeding on probing, probing pocket depth and probing attachment level measurements are discussed. The errors inherent in the various measurements are analyzed and suggestions are presented describing how alterations in any of the above parameters could be identified and presented in a clinical trial. Of concern for the statistical analysis of clinical data of periodontal disease is the definition of the "experimental unit". For a number of years, the "experimental unit" in periodontal trials was the patient. It is clear, however, that different sites within the same individual show different patterns of disease progression and lesion morphology and often respond differently to periodontal therapy. Statistical analyses must consequently be designed which recognize differences in site-to-site infection and lesion morphology within a common host. Until such analyses are available, the investigator should be wary of pooling data within the same individual, since such pooling may obscure meaningful alternatives which may take place in individual periodontal sites. Some goals of periodontal therapy are subsequently identified. 4 goals are discussed more in detail, namely: to establish conditions which will allow the patient to maintain a dentition without further breakdown of the periodontium; to reduce pocket depth to establish an anatomy in the dentogingival region which with proper maintainance care will prevent the re-establishment of the subgingival infection; to gain attachment as a result of treatment; to assess the effect of a certain chemotherapeutic agent on periodontal disease.     

Evaluation of efficacy of chemiluminescence for diagnosis of leukoplakia

ObjectiveLeukoplakia is the most common potentially malignant disorder preceding oral cancer. Chemiluminescence has been developed as an adjunct to conventional examination for the diagnosis of these potentially malignant disorders. This study was conducted to assess the efficacy of chemiluminescence in the diagnosis of leukoplakia and to compare the results with histopathological examination.Study designA total of 50 patients with leukoplakia were included from the outpatients attending the Department of Oral Medicine and Radiology, Dental Hospital, Bengaluru, Karnataka, India. These patients were subjected to conventional oral examination followed by chemiluminescent examination with Vizilite (Zila, Fort Collins, CO, USA) and biopsy for histopathological confirmation.ResultsThe sensitivity, specificity, positive predictive value, and negative predictive value of chemiluminescence were 93.75%, 55.56%, 78.95%, and 83.3%, respectively. The overall accuracy of chemiluminescence was 80%. A statistically significant association was observed between histopathology results and chemiluminescence results.ConclusionAlthough it is an easy, safe, minimal time consuming, and noninvasive technique, it has only adjunctive utility and it does not replace biopsy for the diagnosis of leukoplakia.     

颌骨动静脉畸形的栓塞治疗

目的：总结直接穿刺结合经血管内介入栓塞治疗颌骨动静脉静脉畸形的经验。方法：收治凳骨动静脉畸形患者6例,均进行了介入栓塞治疗。采用的栓塞材料为附凝血棉纤毛的螺圈,聚乙烯醇泡沫微粒和二氰基丙烯酸对丁酯。数字减影颈动脉造影在PHILIPSV300下完成。结果6例颌骨动静脉畸形患者中4,例急性出血得到了快速、有效控制,1例慢性渗血的右下 骨动静脉畸形患者,介入栓塞治疗,拔除松动的右下凳第一磨牙,有效地控制了出血,另1例伴局部软组织搏动性膨隆的上凳骨动静脉畸形患者,介入治疗后膨隆的搏动性得到明显改善,栓塞治疗后分别随访3－24个月,均未发现有口腔内渗血或出血。随访的X线片上,病灶区可见新骨形成。结论：局部穿刺结合经血管内介入栓塞治疗颌骨动静畸形是一种安全、有效的治疗方法。     

正畸患者切牙影像失真发生情况分析

目的研究正畸患者曲面体层片上的切牙影像失真发生情况，并分析其原因。 方法从中山大学附属口腔医院放射科影像数据库中选取500例正畸患者的曲面体层片和头影测量侧位片，所有曲面体层片均采用咬合杆投照，分别从切牙牙体影像放大、缩小、牙根变短、根尖模糊等评价指标分析上下颌切牙影像失真的发生情况，在头影测量侧位片上测量中切牙根尖-对颌切牙切缘的距离，探讨切牙影像失真发生的原因。采用SPSS 19.0统计软件对所得数据进行统计学检验。 结果500例患者中，切牙牙体影像正常者共417例，切牙牙体影像失真者共83例，影像失真发生率16.6%，其中切牙牙体影像放大17例、牙体影像缩小0例、牙根变短30例，牙根影像变短伴模糊36例。影像失真患者的根尖-切缘距离大于影像正常的患者，差异有统计学意义（F = 5 187.18，P = 0）；影像失真患者的覆盖值大于影像正常的患者，差异有统计学意义（F>477，P = 0）。 结论严重牙颌面畸形如反 、深覆盖是导致曲面体层片的切牙影像失真的主要原因之一。     

正常青年Monson球面半径的测量研究

目的测量正常青年Monson球面半径。方法选择60名(男30名,女30名)正常青年制取全口印模,应用立体摄影成像的原理与方法对Monson球面半径进行测量和统计学处理。结果Monson球面的半径平均为10.173 cm,大于理论值10.160 cm,差异有显著性(P<0.01);男、女性球面半径差异无显著性。结论本实验所得到的数据可作为全口义齿修复中记录颌位关系的一个参量。     

鼻测量法的进展

唇裂术后继发畸形是指唇裂修复术后,仍遗留或继发于手术操作和生长发育变化而表现出来的一类畸形[1]。包括唇畸形、鼻畸形和颌骨畸形。其修复较原发性唇裂修复更复杂,更灵活多变。而导致其修复复杂性的一个重要原因即是局部组织结构复杂变异和缺乏可靠的三维测量手段[2],鼻畸形